#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001

int main(){
	
	int H,W,N;
	cin>>H>>W>>N;
	
	vector A(H,vector<int>(W));
	rep(i,H){
		rep(j,W){
			scanf("%d",&A[i][j]);
		}
	}
	
	vector dx = {0,0,1,-1},dy = {1,-1,0,0};
	
	vector<bool> ok(N-1,true);
	
	rep(i,H){
		rep(j,W){
			rep(k,4){
				int ii = i+dx[k],jj = j+dy[k];
				if(ii<0||ii>=H||jj<0||jj>=W)continue;
				if(A[i][j] <= A[ii][jj]){
					if(A[i][j]+1==A[ii][jj]){
						ok[A[i][j]-1] = false;
					}
				}
			}
		}
	}
	int ans = N;
	rep(i,ok.size()){
		if(ok[i])ans--;
	}
	cout<<ans<<endl;
	
	return 0;
}