数据过水

#include <bits/stdc++.h>
using namespace std;
signed main(){
    int n,a,b,ans = 0,fl = 1;
    scanf("%d%d%d",&n,&a,&b);
    while(n > 0) {
        if(n <= a) {
            ans += n;
            n = 0;
        } else{
            if(fl) {
                n -= a;
                n -= b;
                ans += a;
                fl = 0;
            }else{
                n -= (a+1);
                ans += a;
            }
        }
    }printf("%d",ans);
    return 0;
}