嗯嗯

谢谢义父

#include <bits/stdc++.h>
const int N = 370;
using namespace std;
int m, n;
int a[N];
int main() { cin >> a[1] >> a[2] >> m >> n; for (int i = 3; i <= n; i++) { a[i] = a[i-1] + a[i-2];
if (a[i] >= m) {
n = i;
break;
} } int ans = 0; for (int i = 1; i <= n; i++) { ans += a[i];
}

cout << ans << endl; 
return 0; 

}