#include <bits/stdc++.h>
//#include <atcoder/all>
//using namespace atcoder;
//using mint = modint998244353;
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
using ll= long long;
using ull=unsigned long long;
using ldo =long double;

template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define all(...) std::begin(__VA_ARGS__), std::end(__VA_ARGS__)
#define rall(...) std::rbegin(__VA_ARGS__), std::rend(__VA_ARGS__)
const ll INF = 1e18;


#define OVERLOAD_sum(_1, _2, _3,_4, name, ...) name
template<typename T>ll sum1(T &a){ll ans = 0;for(ll i=0;i<a.size();i++)ans+=a[i];return ans;}
template<typename T>ll sum2(T &a,ll start){ll ans = 0;for(ll i=start;i<a.size();i++)ans+=a[i];return ans;}
template<typename T>ll sum3(T &a,ll start,ll en){ll ans = 0;for(ll i=start;i<en;i++)ans+=a[i];return ans;}
template<typename T>ll sum4(T &a,ll start,ll en,ll tolerance){ll ans = 0;for(ll i=start;i<en;i+=tolerance)ans+=a[i];return ans;}
#define sum(...) OVERLOAD_sum(__VA_ARGS__,sum4, sum3, sum2, sum1)(__VA_ARGS__)

#define OVERLOAD_rep(_1, _2, _3,_4, name, ...) name
#define rep1(i,n) for(ll i = 0; i < (ll)(n); i++)
#define rep2(i,n,k) for(ll i = k; i < (ll)(n); i++)
#define rep3(i,n,k,tolerance) for(ll i = k; i < (ll)(n); i+=tolerance)
#define rep(...) OVERLOAD_rep(__VA_ARGS__, rep3, rep2, rep1)(__VA_ARGS__)

void print(){ putchar('\n'); }
void print(bool a){ printf("%d", a); }
void print(int a){ printf("%d", a); }
void print(unsigned a){ printf("%u", a); }
void print(long long a){ printf("%lld", a); }
void print(unsigned long long a){ printf("%llu", a); }
void print(char a){ printf("%c", a); }
void print(char a[]){ printf("%s", a); }
void print(float a){ printf("%.15f", a); }
void print(double a){ printf("%.15f", a); }
void print(long double a){ printf("%.15Lf", a); }
void print(const string& a){ rep(i,a.size()) print(a[i]); }
void print(vector<ll>& a){rep(i,a.size(),0){print(a[i]);if(i!=a.size()-1)print(' ');else print();}}
void print(vector<string>& a){rep(i,a.size(),0){print(a[i]);if(i!=a.size()-1)print(' ');else print();}}

void println(){ putchar('\n'); }
void println(bool a){ printf("%d\n", a); }
void println(int a){ printf("%d\n", a); }
void println(unsigned a){ printf("%u\n", a); }
void println(long long a){ printf("%lld\n", a); }
void println(unsigned long long a){ printf("%llu\n", a); }
void println(char a){ printf("%c\n", a); }
void println(char a[]){ printf("%s\n", a); }
void println(float a){ printf("%.15f\n", a); }
void println(double a){ printf("%.15f\n", a); }
void println(long double a){ printf("%.15Lf\n", a); }
void println(const string& a){ rep(i,a.size()) print(a[i]); print();}
void println(vector<ll>& a){rep(i,a.size(),0){print(a[i]);print();}}
void println(vector<string>& a){rep(i,a.size(),0){print(a[i]);print();}}

int main() {
    string S;
    cin>>S;
    vector<ll> z;
    ll m_len=0,h=0;
    rep(i,S.size()){
        if(S[i]=='<'){
            z.push_back(i);
        }
        if(S[i]=='>'){
            if(z.empty())
                continue;
            if(z.back()==i-1){
                z.clear();
                h = 0;
                continue;
            }
            m_len+=i-z.back()+1-h;
            h+=i-z.back()+1;
            z.pop_back();
        }
    }
    println(S.size()-m_len);
}