201
Lean.Expr.app
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        (Lean.Expr.app (Lean.Expr.app (Lean.Expr.const `f []) (Lean.Expr.const `b [])) (Lean.Expr.const `b [])))))
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    (Lean.Expr.app
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        (Lean.Expr.app (Lean.Expr.app (Lean.Expr.const `f []) (Lean.Expr.const `b [])) (Lean.Expr.const `b []))))
    (Lean.Expr.app
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201
f
b