#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<long long> VL;
typedef vector<VL> VVL;
typedef long long LL;
#define all(a) (a).begin(), (a).end()
#define Yes(n) cout << ((n) ? "Yes" : "No"  ) << endl
#define ALL(a)  (a).begin(),(a).end()
#define pb push_back

int main() {
  string s;cin>>s;
  int n=s.size();
  int ans=n;
  int b=0,a,mod=-1;
  stack<int> B;
  rep(i,n){
    if(s[i]=='<'){mod=1;B.push(b); b=0;}
    if(s[i]=='>'){
      if(b>0){ans-=(b+2);
        if(B.size()>0){
          b=B.top();B.pop();
        }
        else{
          b=0;mod=-1;
        }
      }
      else{
        b=0;
        while(B.size()>0){B.pop();}
        mod=-1;
      }
    }
    if(s[i]=='='&&mod==1){b++;}
  }
  cout<<ans<<endl;
}