hb(u,v);

hb(e[i].u,e[i].v+n);
hb(e[i].v,e[i].u+n);

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn(1e5+10);
int n,m;
struct node{
	int u,v,w;
}e[maxn];
int f[maxn];
int find(int x){
	if(f[x]==x){
		return x;
	}
	return f[x]=find(f[x]);
}
void hb(int x,int y){
	x=find(x),y=find(y);
	if(x!=y){
		f[x]=y;
	}
	return;
}
bool cmp(node a,node b){
	return a.w>b.w;
}
int main(){
//	freopen("A.in","r",stdin);
//	freopen("A.out","w",stdout);
	cin>>n>>m;
	for(int i(1);i<=m;i++){
		cin>>e[i].u>>e[i].v>>e[i].w;
	}
	for(int i(1);i<=n*2;i++){
		f[i]=i;
	}
	sort(e+1,e+m+1,cmp);
	for(int i(1);i<=m;i++){
		int u(find(e[i].u)),v(find(e[i].v));
		if(u==v){
			cout<<e[i].w<<'\n';
			return 0;
		}
		hb(e[i].u,e[i].v+n);
		hb(e[i].v,e[i].u+n);
	}
	cout<<0<<'\n';
	return 0;
}
/*
4 6
1 4 2534
2 3 3512
1 2 28351
1 3 6618
2 4 1805
3 4 12884
*/

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn(1e5+10);
int n,m;
int f[maxn];
struct node{
	int x;
	char ch;
}a[maxn];
int find(int x){
	if(f[x]==x){
		return x;
	}
	return f[x]=find(f[x]);
}
void hb(int x,int y){
	x=find(x),y=find(y);
	if(x!=y){
		f[x]=y;
	}
}
int main(){
//	freopen("B.in","r",stdin);
//	freopen("B.out","w",stdout);
	cin>>n>>m;
	for(int i(1);i<=n*n+n;i++){
		f[i]=i;
	}
	int cnt(0);
	for(int i(1);i<=m;i++){
		int x,y;
		char ch;
		cin>>x>>y>>ch;
		if(ch=='D'&&x+1>n){
			cnt++;
			continue;
		}
		if(ch=='R'&&y+1>n){
			cnt++;
			continue;
		}
		a[i].ch=ch;
		a[i].x=x*n+y;
	}
	for(int i(1);i<=m;i++){
		if(a[i].ch=='D'){
			int u(find(a[i].x)),v(find(a[i].x+n));
			if(u==v){
				cout<<i<<'\n';
				return 0;
			}
			hb(u,v);
		}else{
			int u(find(a[i].x)),v(find(a[i].x+1));
			if(u==v){
				cout<<i<<'\n';
				return 0;
			}
			hb(u,v);
		}
	}
	cout<<"draw\n";
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
#define ll long long
const int maxn(1e5+10);
int n,m;
int f[maxn];
struct node{
	int x;
	char ch;
}a[maxn];
int find(int x){
	if(f[x]==x){
		return x;
	}
	return f[x]=find(f[x]);
}
void hb(int x,int y){
	x=find(x),y=find(y);
	if(x!=y){
		f[x]=y;
	}
}
int js(int x,int y){
	return (x-1)*n+y;
}
int main(){
//	freopen("B.in","r",stdin);
//	freopen("B.out","w",stdout);
	cin>>n>>m;
	for(int i(1);i<=n*n+n;i++){
		f[i]=i;
	}
	int cnt(0);
	for(int i(1);i<=m;i++){
		int x,y;
		char ch;
		cin>>x>>y>>ch;
		if(ch=='D'){
			int u(js(x,y)),v(js(x+1,y));
			u=find(u),v=find(v);
			if(u==v){
				cout<<i<<'\n';
				return 0;
			}
			hb(u,v);
		}else{
			int u(js(x,y)),v(js(x,y+1));
			u=find(u),v=find(v);
			if(u==v){
				cout<<i<<'\n';
				return 0;
			}
			hb(u,v);
		}
	}
	cout<<"draw\n";
	return 0;
}

#include <bits/stdc++.h>
#define N 200010
using namespace std;
int ans;
int A,B,P,cnt,p[N],vis[N];
int fa[N];
int find(int x){
	if(fa[x]==x){
		return x;
	}
	return fa[x]=find(fa[x]);
}
void hb(int x,int y){
	x=find(x),y=find(y);
	if(x!=y){
		fa[x]=y;
	}
}
int main(){
    cin>>A>>B>>P;
    for(int i=A;i<=B;i++){
    	fa[i]=i;
	} 
    for(int i(2);i<=B;i++){
        if(!vis[i]){
        	p[++cnt]=i;
		}
        for(int j(1);j<=cnt&&p[j]*i<=B;j++){
            vis[p[j]*i]=1;
            if(!i%p[j]){
            	break;
			}
        }
    } 
    for(int i=1;i<=cnt;i++)
    if(p[i]>=P){
    	int t((A+p[i]-1)/p[i]*p[i]);
    	for(int j(t+p[i]);j<=B;j+=p[i]){
    		hb(t,j);
		}
    }
    for(int i(A);i<=B;i++){
    	if(fa[i]==i){
    		ans++;
		}
    }
    cout<<ans<<'\n';
}