写三个循环找即可

#include<bits/stdc++.h>
using namespace std;
int day[15];
int main(){
    for(int i = 1;i <= 7;i++){
        int a,b; cin >> a >> b;
        day[i] = a + b;
    }
    bool right = 1;
    for(int i = 1;i <= 7;i++){
        if(day[i] > 8) right = 0;
    }
    if(right) cout << 0;
    else{
        int ans = 0,now = -1;
        for(int i = 1;i <= 7;i++){
            if(now < day[i]){
                now = day[i];
                ans = i;
            }
        }
        cout << ans;
    }
    return 0;
}