#include<bits/stdc++.h> #define N 50005 using namespace std; int n,m,l,a[N]; bool check(int d){ int t=0,cnt=0; for(int i=1;i<=n;i++){ if(a[i]-t<d) cnt++; else t=a[i]; } if(l-t<d) cnt++; return cnt<=m; } int main() { cin>>l>>n>>m; for(int i=1;i<=n;i++){ cin>>a[i]; } int left=1,right=l+1,mid; while(left+1<right){ mid=(left+right)>>1; if(check(mid)) left=mid; else right=mid; } cout<<left; return 0; }