#include <stdio.h>
int main(){
int n;
int arr[500] = {0};
int flag[500] = {-1};
int p[500] = {0};
int max = 0; //记录最大赛道
scanf("%d",&n);
for(int i = 0; i < 500; i++) flag[i] = -1;
for(int i = 0; i < n; i++){
int a,b;
scanf("%d%d",&a,&b);
int f = a / 500; //计算在第几赛道,也就是标志
int g = a % 500; //计算在赛道的第几位,也就是标志下标
if(f > max) max = f;
if(flag[g] < 0){ //判断是否有键值
arr[g] += b;
flag[g] = f;
}else if((500 * f + g + p[g]) == a){ //判断是否是同键值
arr[g] += b;
}else{ //键位被占向前移
for(int j = g; j < 500; j++){
if(flag[j] == -1 || (500 * f + g + p[g]) == a){
arr[j] += b;
flag[j] = f;
p[j] = j - g;
}
}
}
}
for(int i = 0; i <= max; i++){
for(int j = 0; j < 500; j++){
if(flag[j] == i && arr[j] > 0){
printf("%d %d\n",(500 * i + j + p[j]),arr[j]);
}
}
}
return 0;
}