#include <iostream>#include <cstdio>#include <cmath>#include <string.h>using namespace std;const int N = 100010;typedef long long LL;LL num[N];int main(){//freopen("1.txt","r",stdin);int n;while(scanf("%d",&n) != EOF){LL maxvalue = 0,rp = 0;memset(num,0,sizeof(num));for(int i = 0; i < n; ++i){ scanf("%lld",&num[i]); if(num[i] > maxvalue) maxvalue = num[i];}LL k;scanf("%lld",&k);if(k == 1){ printf("%lldn",maxvalue); continue;}LL lp = 1,ans = 0;rp = maxvalue;while(lp <= rp){ LL mid = (lp + rp) / 2, sum = 0; for(int i = 0; i < n; ++i){ if(num[i] > mid){ long long xx = ceil((num[i] - mid ) * 1.0 / (k - 1) ); sum += xx; } } if(sum <= mid){ ans = mid; rp = mid - 1; } else lp = mid + 1;}printf("%lldn",ans);}return 0;}
