[noj 1555] The Sum of F(x) and G(x)

#include<iostream>
#include<cstdio>
#include<map>
using namespace std;

int main()
{
int n, m;
map<int, int> mp;
int a, b;
while(~scanf("%d%d", &n, &m))
{
mp.clear();
for(int i = 0; i < n+m; i++)
{
scanf("%d%d", &a, &b);
mp[b] += a;
}
map<int, int>::iterator it = mp.end();
for(it--; it != mp.begin(); it--)
printf("%d %d\n", it->second, it->first);
printf("%d %d\n", it->second, it->first);
}
return 0;
}