// Judges with GCC >= 12 only needs Ofast
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// MLE optimization
// #pragma GCC optimize("conserve-stack")
// Old judges
// #pragma GCC target("sse4.2,popcnt,lzcnt,abm,mmx,fma,bmi,bmi2")
// New judges. Test with assert(__builtin_cpu_supports("avx2"));
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
// Atcoder
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
- insert(x),erase(x)
- find_by_order(k): return iterator to the k-th smallest element
- order_of_key(x): the number of elements that are strictly smaller
*/
#include<bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
uniform_real_distribution<> pp(0.0,1.0);
#define int long long
#define ld long double
#define pii pair<int,int>
#define piii pair<int,pii>
#define mpp make_pair
#define fi first
#define se second
const int inf=1e18;
const int mod=998244353;
const int maxn=200005;
const int bl=650;
const int maxs=655;
const int maxm=200005;
const int maxq=1000005;
const int maxl=20;
const int maxa=1000000;
const int root=3;
int power(int a,int n){
int res=1;
while(n){
if(n&1) res=res*a%mod;
a=a*a%mod;n>>=1;
}
return res;
}
const int iroot=power(3,mod-2);
const int base=101;
int cc[2];
void solve(){
string s,t;cin >> s >> t;
int cnt=0,num=0,len=(int)t.length(),n=(int)s.length();
for(int i=0;i<=n-len;i++) cnt+=(t==s.substr(i,len));
for(int i=0;i<n;i++) num+=(s[i]==t[0]);
if(len==1){
if(cnt) cout << -1 << '\n';
else cout << 0 << '\n';
}
else if(len==2){
if(t[0]==t[1] && num>(n+1)/2) cout << -1 << '\n';
else cout << cnt << '\n';
}
if(len==3){
if(t[0]!=t[2]) cout << cnt << '\n';
else if(t[0]!=t[1]) cout << (cnt+1)/2 << '\n';
else{
if(num>(2*(n/3)+n%3)) cout << -1 << '\n';
else{
int res=0;s+=(t[0]^1);
vector<int> d;
int cur=0;
for(int i=0;i<(int)s.length();i++){
if(s[i]!=t[0]){
if(cur<=1) cc[cur]++;
else d.push_back(cur);
cur=0;
}
else cur++;
}
for(int x:d){
while(x>=4 && cc[0]) cc[0]--,x-=2,res++;
while(x>=3 && cc[1]) cc[1]--,x--,res++;
if(x>=3){
cc[0]--;
res++;
}
}
cout << res << '\n';
}
}
}
}
signed main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);cout.tie(NULL);
int test=1;//cin >> test;
while(test--) solve();
}
