#include<bits/stdc++.h> using namespace std; int c,d,i,n,m,k,x,j=1000000007; string s; main(){ cin>>s; for(i=s.size()-1;i>=0;i--){ if(s=='b')c++;else{ k+=c;c*=2;k%=j;c%=j; } } cout<<k; }

#include<iostream> main(){int n;std::cin>>n;std::cout<<(n-1)/2;}

#include <cstdio> int n; int main (){ scanf("%d", &n); for (int i = 0; i <...

#include <iostream> int l,r; int main() { std::cin>>l>>r; std::cout<<(l==r ? l:2); return 0; }

#pragma warning(disable:4996) #include <stdio.h> #include <iostream> #include <iomanip> #include <vector> #include <algorithm> #include <string.h> #include <stdlib.h> #include <assert.h> #include <cmath> #include <map> #include...

#include<bits/stdc++.h> using namespace std; const int maxn=100000+10; int b,n,flag=1,dp; struct node { int id,x; }a; int cmp(node a,node b) { return a.x>b.x; } int...

#include <bits/stdc++.h> using namespace std; int main(){ int n, num = 0, x, sum =...

#include <bits/stdc++.h> using namespace std; string s; int main() { int n, t, ans; ans = INT_MAX; cin>>n; string temp; for(int...

#include<iostream> using namespace std; main() { string s;cin>>s; int n=s.size(),cnt=0; for(int i=0;i<n/2;i++) { if(s!=s)cnt++; } cout<<(cnt==1||cnt==0&&n%2==1?"YES":"NO")<<endl; }

#include<cstdio> #include<cstring> #include<algorithm> #include<cctype> #include<ctime> #include<cstdlib> #include<string> #include<queue> #include<cmath> #include<set> #include<map> #include<bitset> #include<vector> #define rep(x,a,b) for (int x=int(a);x<=(int)(b);x++) #define drp(x,a,b) for (int x=int(a);x>=(int)(b);x--) #define cross(x,a) for (int...

#include <bits/stdc++.h> #define MAXN (1000000) #define MAXM (6) #define mod (1000000007) #define ll long long int n; int...

import java.util.ArrayList; import java.util.Scanner; /* 4 10 2 4 6 8 4 10 2 9 1 0 */ public class...