#include<bits/stdc++.h> using namespace std; int f(int n) { int r,b=0; if(n==1) { r = 1; b+=r; } else { r = f(n-1)+n; } return r; } int main() { int n; cin>>n; cout<<f(n); } /************************************************************** Problem: 1148 User: wuyichen Language: C++ Result: Wrong Answer ****************************************************************/