#include<bits/stdc++.h> using namespace std; int main(){ int n,k; cin >> n >> k; long long int t[n]; long long int btw[n-1]; cin >> t[0]; for(int i=1;i<n;i++){ cin >> t[i]; btw[i-1] = t[i]-t[i-1]-1; } sort(btw,btw+n-1,greater<>()); long long int time=t[n-1]-t[0]+1; int match = 0; while(match<k-1){ time-=btw[match]; match++; } cout << time; }