//g++ -o sol sol.cpp //cd C:\Users\Asus-1\OneDrive\Desktop #include <bits/stdc++.h> using namespace std; #define ld long double #define int long long const int INF = 1e18; const int mod=1e9+7; #define S(a) a.begin(),a.end() #define pb push_back #define READ(l , r , a) for(int i = l;i <= r;i++) cin >> a[i] #define printV(l , r , a) for(int i = l;i <= r;i++) cout << a[i] << ' '; #define pii pair < int , int > #define FOR(i , l , r) for(int i = l;i <= r;i++) #define mp make_pair void solve(){ int n,k; cin>>n>>k; --k; vector<int>a(n); for(int &i:a) cin>>i; vector<int>all; for(int i=0;i<n-1;i++) all.pb(a[i+1]-a[i]); sort(all.rbegin(),all.rend()); int res=a[n-1]-a[0]+1; for(int i=0;i<k;i++) res-=(all[i]-1); cout<<res<<endl; } signed main(){ ios_base::sync_with_stdio(); cin.tie(0); cout.tie(0); int T=1;//cin>>T; while(T--) solve(); }