10013.cpp

#include<iostream>
#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
int main(){
        int test,i;
        scanf("%d",&test);
        for(i=0;i<test;i++){
            int n,j;
            scanf("%d",&n);
            int sum[n], carry=0;
            memset(sum, 0, sizeof(sum));
            for(j=0; j<n; j++){
                    int a=0, b=0;
                    scanf("%d%d",&a,&b);
                    sum[j] = a + b;
            }
            for(j=n-1 ;j>=0; j--){
                                int temp = sum[j];
                                sum[j] = (temp+carry)%10;
                                carry = (temp+carry)/10;
            }
            for(j=0;j<n;j++)
                            printf("%d",sum[j]);
            printf("\n");
            if(i < test-1)
                      printf("\n");
    }
    //system("pause");
    return 0;
}