爆切数论。

#include<bits/stdc++.h>
#define int long long
#define INF 0x3f3f3f
using namespace std;
int a,b;
signed main(){
	while(cin>>a>>b)
		cout<<a+b-__gcd(a,b)<<"\n";
	return 0;
}

C++ :

#include <cstdio>
#include <iostream>
#include <cmath>
#include <algorithm>
using namespace std;
typedef long long LL;
LL gcd(LL a,LL b){
    if(b==0) return a; return gcd(b,a%b);
}
int main(){
    LL a,b;
    //freopen("in.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    while(scanf("%lld%lld",&a,&b)!=EOF){
        printf("%lld\n",a+b-gcd(a,b));
    }
    return 0;
}