#include <bits/stdc++.h>
using namespace std;

typedef int64_t i64;
typedef uint64_t ui64;

const int inf=1073741823;
const i64 llinf=4611686018427387903LL;

i64 gcd(i64 a,i64 b){
    i64 t,r;
    if(a<b){
        t=a;
        a=b;
        b=t;
    }
    r=a%b;
    while(r!=0){
        a=b;
        b=r;
        r=a%b;
    }
    return b;
}

int digit(i64 n){
    int t=1;
    while(n>=10){
        n/=10;
        t++;
    }
    return t;
}

int main(void){
    i64 t,a,b;
    scanf("%lli%lli%lli",&t,&a,&b);
    i64 da=t/a;
    i64 db=t/b;
    i64 dg=t/(a/gcd(a,b)*b);
    printf("%lli\n",da+db-dg);
    return 0;
}