#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(a, b) for(int a = 0; a < (b); ++a)
#define st first
#define nd second
#define pb push_back
#define all(a) a.begin(), a.end()
const int LIM=2e5+7;
ll T[LIM];
int main() {
	ios_base::sync_with_stdio(0); cin.tie(0);
	int n, m, q;
	cin >> n >> m >> q;
	rep(i, n) cin >> T[i];
	ll ans=0, ma=T[0];
	rep(i, n-1) ans+=min(T[i], T[i+1]);
	for(int i=2; i<n; ++i) {
		if(T[i]<=T[i-1]) ans+=T[i-1]-T[i];
		else if(T[i]>ma) {
			ans+=T[i]-T[i-1];
			ma=T[i];
		}
	}
	cout << ans << '\n';
}