#define f(i,e)for(i=e+1;i--;)
#define max(p,q)(p<(q)?p=q:p)
char s[110];
dp[110][22][22][22][22];
i,a,b,c,d,t;
main(ans){
	*****dp=1;
	for(gets(s);s[i];i++){
		f(a,20)f(b,a)f(c,b)f(d,c)if(t=dp[i][a][b][c][d]){
			if(s[i]=='K'||s[i]=='?')max(dp[i+1][a+1][b][c][d],t);
			if(s[i]=='U'||s[i]=='?')max(dp[i+1][a][b+1][c][d],t);
			if(s[i]=='R'||s[i]=='?')max(dp[i+1][a][b][c+1][d],t);
			if(s[i]=='O'||s[i]=='?')max(dp[i+1][a][b][c][d+1],t);
			if(s[i]=='I'||s[i]=='?')max(ans,max(dp[i+1][a][b][c][d],d<t?0:t+1));
			max(dp[i+1][a][b][c][d],t);
		}
	}
	ans=!printf("%d",ans-1);
}