#include <bits/stdc++.h>
using namespace std;
#define int long long
const int INF = 1e18;
signed main(){
ios::sync_with_stdio(false);
cin.tie(0);
int n, m;
cin >> n >> m;
if(n == 1){
vector< int > v(m+1);
vector< int > dp(m+1);
vector< int > one(m+1);
vector< int > zero(m+1);
for(int i = 1; i <= m; i++){
cin >> v[i];
zero[i] += zero[i-1];
one[i] += one[i-1];
zero[i] += (v[i] == 0);
one[i] += (v[i] == 1);
}
dp[0] = -INF;
int mini = INF;
for(int i = 1; i <= m; i++){
//cout << "NUMBER " << i << ' ' << "MINI " << mini << endl;
if(mini + zero[i] < one[i-1] + (v[i] == 0)){
dp[i] = mini + zero[i];
if(dp[i]-zero[i-1] <= mini){
mini = dp[i]-zero[i-1];
}
}else{
dp[i] = one[i-1] + (v[i] == 0);
if(dp[i]-zero[i-1] <= mini){
mini = dp[i]-zero[i-1];
}
}
//cout << "DP " << dp[i] << endl;
}
int ans = INF;
for(int i = 1; i <= m; i++){
ans = min(ans, one[m]-one[i] + dp[i]);
}
cout << ans << endl;
}
}
