大意: 求n!在b进制下末尾0的个数
等价于求n!中有多少因子b, 素数分解一下, 再对求出所有素数的最小因子数就好了
ll n, b;
vector<pli> A, res; void factor(ll x) {
int mx = sqrt(x+0.5);
REP(i,2,mx) if (x%i==0) {
int t = 0;
while (x%i==0) x/=i,++t;
A.pb(pli(i,t));
}
if (x>1) A.pb(pli(x,1));
} int main() {
cin>>n>>b;
factor(b);
int sz = A.size();
ll ans = 1e18;
REP(i,0,sz-1) {
ll t = 0, num = n/A[i].x;
while (num) t+=num, num/=A[i].x;
ans = min(ans, t/A[i].y);
}
printf("%lld\n", ans);
}