ZOJ 1003 Crashing Balloon

#include<iostream>
#include<vector>
#include<string>
#include<set>
#include<map>
#include<algorithm>
#include<queue>
#include<list>
#include<stack>
#include<cstdio>
#include<fstream>
#include<numeric>
#include<functional>
#include<utility>
#include<memory>
#include<iomanip>
using namespace std;

int n, m;
bool flagA, flagB;

void dfs(int n,int m,int k){
	if (n == 1 && m == 1){
		flagA = true;
		flagB = true;
		return;
	}
	if (m == 1){
		flagB = true;
	}
	for (int t = k + 1; t <= 100; t++){
		if (n%t == 0){
			dfs(n/t,m,t);
			if (flagA) return;
		}
		if (m%t == 0){
			dfs(n, m / t,t);
			if (flagA) return;
		}
	}
}

int main(){
	while (cin >> n >> m){
		if (n < m){
			swap(n, m);
		}
		flagA = false;
		flagB = false;
		dfs(n,m,1);
		int res = n;
		if (flagA == false && flagB == true){
			res = m;
		}
		cout << res << endl;
	}
	return 0;
}