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Given a string S, the task is to count number of subsequences of the form a^{i}b^{j}c^{k}, where i >= 1, j >=1 and k >= 1.

**Note:**

1. Two subsequences are considered different if the set of array indexes picked for the 2 subsequences are different.

2. For large test cases, output value will be too large, return the answer MODULO 10^9+7

**Example 1:**

**Input:**
S = "abbc"
**Output:** 3
**Explanation**: Subsequences are abc, abc and abbc.

â€‹

**Example 2:**

**Input**:
S = "abcabc"
**Output:** 7
**Explanation**: Subsequences are abc, abc,
abbc, aabc abcc, abc and abc.

**Your Task:**

You don't need to read input or print anything. Your task is to complete the function **fun() **which takes the string S as input parameter and returns the number of subsequences which follows given condition.

**Expected Time Complexity: **O(Length of String).

**Expected Auxiliary Space: **O(1) .

**Constraints:**

1 <= |S| <= 10^{3}

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Count subsequences of type a^i, b^j, c^k

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