const stdin = require("fs").readFileSync("/dev/stdin", "UTF8");
const [t, a, b] = stdin.split(/\S/).filter(x=>x).map(x=>BigInt(x));

function gcd(a, b) {
    function gcd_core(a, b) {
        return b ? gcd_core(b, a % b) : a;
    }
    return a > b ? gcd_core(a, b) : gcd_core(b, a);
}

const g = gcd(a, b);
const l = a * b / g;
const bus1 = (t + a - 1) / a;
const bus2 = (t + b - 1) / b;
const busomni = (t + l - 1) / l;
console.log(bus1 + bus2 - busomni);