#include<bits/stdc++.h> using namespace std; int main(){ int i,j,n,m,k,ans=0,t,tt,t1,t2; char a; cin>>n>>m>>k; for(i=1;i<=n;i++){ for(j=1;j<=m;j++){ cin>>a; if(a=='#'){ ans++; } else if(a=='@') t=i,tt=j; else if(a=='+') t1=i,t2=j; } } if(ans<=k*2) cout<<abs(t-t1)+abs(t2-tt); else cout<<-1; return 0; }