题解

#include<bits/stdc++.h>
using namespace std;
int main(){
long long n,s=0;
cin>>n;
for(long long a=0;a<=n/5;a++){
int b=(n-7a)/4;
int c=n-b-a;
if((n-a-b)%3==0 and (n-7a)%4==0 and c>=0 and b>=0){
s+=1;
}
}
cout<<s;
}