1 #include<cstdio>
2 #include<cstring>
3 #include<iostream>
4 #include<algorithm>
5 #include<deque>
6 #include<cstdlib>
7 using namespace std;
8 typedef long long INT;
9 const INT MOD = 1000000007;
10 const int maxn = 2000000+5;
11 char str[maxn],temp[maxn];
12 int get_num(INT s,INT t)
13 {
14 for(int i = 0;i < t;++i)
15 {
16 s = s >> 1;
17 if(s == 0)
18 return 0;
19 }
20 return s;
21 }
22 int main()
23 {
24 while(gets(temp))
25 {
26 if(temp[0] == '#')
27 break;
28 int len = strlen(temp),f = 0;
29 for(int i = 0;i < len; ++i)
30 if(temp[i] != ' ')
31 str[f++] = temp[i];
32 str[f] = NULL;
33 len = f;
34 deque<INT> que1;
35 deque<char> que2;
36 //预处理
37 for(int i = 0;i < len-2;++i)
38 if(str[i] == '>' && str[i+1] == '>' && str[i+2] != '>')
39 str[i] = str[i+1] = '^';
40 char ss[20]; //缓存数字
41 for(int i = 0;i < len;++i)
42 {
43 if(str[i] == 'S' || str[i] == 's')
44 {
45 i++;
46 que2.push_front('<');
47 }
48 if(str[i] == '>')
49 {
50 INT tt = *que1.begin();
51 que1.pop_front();
52 que2.pop_front(); //计算完后把'<'弹出来
53 tt *= tt;
54 tt %= MOD;
55 if(*que2.begin() == '^')
56 {
57 INT tt2 = *que1.begin();
58 que1.pop_front();
59 que1.push_front(get_num(tt2,tt));
60 que2.pop_front();
61 }
62 else que1.push_front(tt);
63 }
64 if(str[i] == '^')
65 {
66 i++;
67 que2.push_front('^');
68 }
69 if(str[i] >= '0' && str[i] <= '9')
70 {
71 int ll = 0;
72 while(str[i] >= '0' && str[i] <= '9')
73 {
74 ss[ll++] = str[i];
75 i++;
76 }
77 i--;
78 ss[ll] = NULL;
79 int tt = atoi(ss);
80 if(*que2.begin() == '^')
81 {
82 int tt2 = *que1.begin();
83 que1.pop_front();
84 que2.pop_front();
85 que1.push_front(get_num(tt2,tt)); //get_num计算tt2 >> tt之后压回到栈中
86 }
87 else que1.push_front(tt);
88 }
89 }
90
91 printf("%d\n",*que1.begin());
92 que2.clear();
93 que1.clear();
94 }
95 return 0;
96 }
