#include<bits/stdc++.h>
using namespace std;
const int N=105;
int n,m,Case;
char a[N][N];
int f(int x,int y,int dx,int dy) {
	int res=0;
	while(1) {
		x+=dx,y+=dy;
		if(!x||!y||x>n||y>m)break;
		res+=a[x][y]!='.';
	}return res;
}
void solve() {
	scanf("%d%d",&n,&m);int ans=0;
	for(int i=1;i<=n;i++)scanf("%s",a[i]+1);
	for(int i=1;i<=n;i++) {
		for(int j=1;j<=m;j++) {
			if(a[i][j]!='.') {
				int s1=f(i,j,-1,0),s2=f(i,j,1,0),s3=f(i,j,0,-1),s4=f(i,j,0,1);
				if(s1+s2+s3+s4==0){ans=-1;break;}
				ans+=(a[i][j]=='^'&&!s1)+(a[i][j]=='v'&&!s2)+(a[i][j]=='<'&&!s3)+(a[i][j]=='>'&&!s4);
			}
		}
	}
	if(ans==-1)printf("Case #%d: IMPOSSIBLE\n",++Case);
	else printf("Case #%d: %d\n",++Case,ans);
}
int main() {
	int tt;scanf("%d",&tt);
	while(tt--)solve();
	return 0;
}