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#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
// P1082 [NOIP2012 提高组] 同余方程
//扩展欧几里得
LL exgcd(LL a, LL b, LL &x, LL &y) {
if (!b) {
x = 1, y = 0;
return a;
}
LL d = exgcd(b, a % b, y, x);
y -= a / b * x;
return d;
}
int main() {
LL a, b;
scanf("%lld %lld", &a, &b);
LL x, y;
exgcd(a, b, x, y);
printf("%d\n", (x % b + b) % b);
return 0;
}