Python solution with simple calculations
\nclass Solution:\n    def strWithout3a3b(self, a: int, b: int) -> str:\n        res=[]\n        d=a-b\n        if d>0:\n            g=min(d,b)\n            res
```\nclass Solution:\n    def strWithout3a3b(self, a: int, b: int) -> str:\n        res=[]\n        d=a-b\n        if d>0:\n            g=min(d,b)\n            res=["aab"]*g\n            a-=2*g\n            b-=g\n        elif d<0:\n            g=min(-d,a)\n            res=["bba"]*g\n            b-=2*g\n            a-=g\n        p=min(a,b)\n        res+=["ab"]*p\n        a-=p;b-=p\n        res+=["a"]*a+["b"]*b\n        return "".join(res)\n```
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