#include<iostream> #include<cstdio> #include<cstring> #include<cstdlib> #define INF 0x7ffffff #define maxn 2000000 using namespace std; long long n,a[maxn],m,ll,rr,l,s,num,mid,ans; int half(int x){ s=0,num=0; for(int i=1;i<=n+1;i++){ num++; s = a[i]; } if(num>m) return 0; return 1; } int main(){ cin >> l >> n >> m; for(long long i = 1;i <= n;i++) cin >> a[i]; a[n + 1] = l; ll=0 ,rr = l; while(ll <= rr){ mid = (ll + rr) / 2; if(half(mid)){ ll = mid + 1; ans = mid; } else rr = mid - 1; } cout << ans; return 0; }