#include <bits/stdc++.h>

using namespace std;
const int M = 1000100;
const long long oo =std::numeric_limits<int>::min();
const int PW = 20;
const int md = int(1e9) + 7;
const int N = int(2e6)+1;
int a[1000001];
long long sum[1000001];
long long ans[1000001];
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int n,m,q;
    cin>>n>>m>>q;
    int x,y;
    x=0,y=0;
    long long ans=q;
    for(int i=0;i<q;i++){
        int cl;
        cin>>cl;
        cl--;
        int x1=cl%m,y1=(cl/m);
        ans+=min(abs(n-max(y1,y)-min(y,y1)),abs(y-y1))+ min(abs(m-max(x1,x)-min(x,x1)),abs(x-x1));
        x=x1,y=y1;
    }
    cout<<ans;
    return 0;
}