为森么后三个点报了RuntimeError?

#include<algorithm>
#include<iostream>
#include<string>
#include<vector>
using namespace std;
int count(string str){
	int ans=0;
	for(int fex=0;fex<=str.length()-3;++fex){
		if(str[fex]=='s'&&str[fex+1]=='o'&&str[fex+2]=='s'){
			++ans;
		};
	};
	return ans;
};
struct node{
	string nme,str;
	int pos;
};
bool compare(node cmp1,node cmp2){
	return cmp1.pos>cmp2.pos;
};
int main(int argc,char **argv){
	ios::sync_with_stdio(false);
	cout.tie(nullptr);
	cin.tie(nullptr);
	int maxn;
	cin>>maxn;
	vector<node> data(maxn);
	for(int iter=0;iter<maxn;++iter){
	    node tmp;
	    cin>>tmp.nme>>tmp.str;
	    tmp.pos=count(tmp.str);
	    data[iter]=tmp;
	};
	stable_sort(data.begin(),data.end(),compare);
	for(int iter=0;iter<maxn;++iter){
		if(data[iter].pos!=data[0].pos){
			break;
		};
		cout<<data[iter].nme<<" ";
	};
	cout<<endl<<data[0].pos;
	return 0;
};