#include <map>
#include <string>
#include <cstdio>
#include <cstring>
#include <sstream>
#include <iostream>
#include <algorithm>
#define M 110
#define MOD 1000000007
using namespace std;
map<string,int> var_map;
int stack[M],top;
int tot;
int Hash(string s)
{
int &re=var_map[s];
if(!re) re=++tot;
return re;
}
struct Matrix
{
int a[M][M];
Matrix() {}
Matrix(int val)
{
memset(a,0,sizeof a);
for(int i=0;i<=tot;i++)
a[i][i]=val;
}
int* operator [] (int i)
{
return a[i];
}
friend Matrix operator * (Matrix x,Matrix y)
{
Matrix z(0);
for(int i=0;i<=tot;i++)
for(int j=0;j<=tot;j++)
for(int k=0;k<=tot;k++)
(z[i][j]+=(long long)x[i][k]y[k][j]%MOD)%=MOD;
return z;
}
friend Matrix Quick_Power(Matrix x,int y)
{
Matrix re(1);
while(y)
{
if(y&1) re=rex;
x=x*x; y>>=1;
}
return re;
}
}matrix[M];
int main()
{
string buffer;
new (&matrix[0])Matrix(1);
while(1)
{
static char s[360];
gets(s);
istringstream stream(s);
stream>>s;
if(s[0]>='a'&&s[0]<='z')
{
static int b[M];
int left=Hash(s);
memset(b,0,sizeof b);
while(stream>>s)
{
if(s[0]>='a'&&s[0]<='z')
{
int right=Hash(s);
for(int i=0;i<=tot;i++)
(b[i]+=matrix[top][right][i])%=MOD;
}
else if(s[0]>='0'&&s[0]<='9')
{
int right=atoi(s);
(b[0]+=right)%=MOD;
}
}
for(int i=0;i<=tot;i++)
matrix[top][left][i]=b[i];
}
else if(s[0]>='0'&&s[0]<='9')
{
stack[top]=atoi(s);
new (&matrix[top])Matrix(1);
}
else if(s[0]'}')
{
matrix[top-1]=Quick_Power(matrix[top],stack[top])*matrix[top-1];
top--;
}
else if(s[0]'R')
{
stream>>s;
int val=Hash(s);
int ans=0;
for(int i=0;i<=tot;i)
(ans+=matrix[0][val][i])%=MOD;
cout<<ans<<endl;
break;
}
}
return 0;
}
