#include <bits/stdc++.h> using namespace std; // Simple Define #define ALISA_MIKHAILOVNA_KUJOU \ ios_base::sync_with_stdio(0); \ cin.tie(0); \ cout.tie(0) #define ARYA_IS_THE_BEST freopen("input.inp", "r", stdin) #define SHE_IS_MY_WIFE freopen("output.out", "w", stdout) #define ll long long #define ull unsigned long long #define fi first #define se second #define vi vector<int> #define vstr vector<string> #define vc vector<char> #define vb vector<bool> #define vpii vector<pair<int, int>> #define pii pair<int, int> #define pill pair<int, long long> #define vpill vector<pair<int, long long>> #define vll vector<long long> #define all(a) a.begin(), a.end() #define rall(a) a.rbegin(), a.rend() #define fr(i, a, b) for (int i = (a); i <= (b); i++) #define fd(i, a, b) for (int i = (a); i >= (b); i--) #define el cout << "\n" #define elif else if // bitwise operator #define MASK(i) (1 << (i)) #define c_bit(i) __builtin_popcountll(i) #define BIT(x, i) ((x) & MASK(i)) #define SET_ON(x, i) ((x) | MASK(i)) #define SET_OFF(x, i) ((x) & ~MASK(i)) #define getbit(x, i) ((x >> i) & 1) void solve() { int n, k; cin>>n>>k; vll t(n,0); for (ll& x: t) cin>>x; if (k>=n){ cout<<n; return; } ll ans=(t[n-1]+1)-t[0]; vll gaps; for (int i=0;i<n-1;i++) gaps.push_back(t[i+1]-(t[i]+1)); sort(rall(gaps)); for (int i=0;i<k-1 && i<gaps.size();i++) ans-=gaps[i]; cout<<ans; } int main() { ALISA_MIKHAILOVNA_KUJOU; int t = 1; // cin >> t; while (t--) solve(); return 0; }