#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<to;x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

int L;
string S;
int dp[2][21][21][21][21][21];

void solve() {
	int i,j,k,l,r,x,y; string s;
	int a,b,c,d,e;
	cin>>S;
	L=S.size();
	
	ZERO(dp);
	int ma=0;
	dp[0][0][0][0][0][0]=1;
	
	FOR(i,L) {
		int cur=i%2,tar=cur^1;
		ZERO(dp[tar]);
		for(a=19;a>=0;a--)
		for(b=20;b>=0;b--)
		for(c=20;c>=0;c--)
		for(d=20;d>=0;d--)
		for(e=20;e>=0;e--) if(dp[cur][a][b][c][d][e]) {
			dp[tar][a][b][c][d][e]=dp[cur][a][b][c][d][e];
			if(S[i]=='K' || S[i]=='?') {
				if(e<20) dp[tar][a][b][c][d][e+1] = 1;
			}
			if(S[i]=='U' || S[i]=='?') {
				if(d<20 && e) dp[tar][a][b][c][d+1][e-1] = 1;
			}
			if(S[i]=='R' || S[i]=='?') {
				if(c<20 && d) dp[tar][a][b][c+1][d-1][e] = 1;
			}
			if(S[i]=='O' || S[i]=='?') {
				if(b<20 && c) dp[tar][a][b+1][c-1][d][e] = 1;
			}
			if(S[i]=='I' || S[i]=='?') {
				if(a<20 && b) {
					dp[tar][a+1][b-1][c][d][e] = 1;
					ma=max(ma,a+1);
				}
			}
		}
		
	}
	cout<<ma<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false);
	FOR(i,argc-1) s+=argv[i+1],s+='\n';
	FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	solve(); return 0;
}