#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int inf=0x3f3f3f3f;int dp[405][25][25];int dfs(int m,int w,int h){ if(dp[m][w][h]!=inf) return dp[m][w][h]; else if(m==0) return dp[m][w][h]=w*h; else { int ans=inf; for(int i=1,lim=w/2+1;i<=lim;i++) for(int k=0;k<=m-1;k++) ans=min(ans,max(dfs(k,i,h),dfs(m-1-k,w-i,h))); for(int i=1,lim=h/2+1;i<=lim;i++) for(int k=0;k<=m-1;k++) ans=min(ans,max(dfs(k,w,i),dfs(m-1-k,w,h-i))); return dp[m][w][h]=ans; }}int main(){ int w,h,m; memset(dp,0x3f,sizeof(dp)); while(scanf("%d%d%d",&w,&h,&m),w||h||m) printf("%dn",dfs(m-1,w,h)); return 0;}
