#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
string S;int a[100000];
int main(){
	cin>>S;
	for(int i=0;i<S.size();i++){
		if(S[i]=='I'){a[i]=1;}
		for(int j=0;j<i;j++){
			if(S[j]=='I' && S[i]=='O' && a[j]%2==1){a[i]=max(a[i],a[j]+1);}
			if(S[j]=='O' && S[i]=='I' && a[j]%2==0){a[i]=max(a[i],a[j]+1);}
		}
	}
	int maxn=0;
	for(int i=0;i<S.size();i++){
		maxn=max(maxn,a[i]);
	}
	if(maxn%2==0 && maxn>=1){maxn--;}
	cout<<maxn<<endl;
	return 0;
}

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SU9PSUlPSU9JSU9JCg==

IOOIIOIOIIOI