#include<bits/stdc++.h> using namespace std; int a1(int n,int m) { int sum=0; for(int i=n; i<=m; i++) { sum+=i; } return sum; } int main() { cout<<a1(1,10)<<endl; cout<<a1(20,30)<<endl; cout<<a1(35,45)<<endl; return 0; }